Compressor for refrigerating machines



June 28, 1932- I c. STEENSTRUP COMPRESSOR FOR REFRIGERATING MACHINESOriginal Filed May 18, 1926 2 Sheets-Sheet 1 2 oooaooooo Hg. l.

Inventor: Christian Steens His flttorneg.

June 28, 1932 v c. STEENSTRUP 1,864,678

COIPBESSOR FOR REFRIGERATING MACHINES Original Filed May 18, 1926 2Sheets-Sheet 2 Fig.4.

A? lllllllnl ////I// [IN] l i 4/ a I 63 I I 7/ 44 I g I I v.2 "l/AIl-WJ" I Inventor: Christian Steenstrup,

Hi5 Aciorneg.

Patented June 28, 1932 UNITED STATES PATENT. orrlcs ofiars'riansrnnusrnur, or sonnnnc'ranr, mew roux, assrenon r emtnaar.manornrccomrm, a coarona'rron or raw Yonx couranssoa ron anrzarenn'armemennms Original application flied Kay 18, 1928, Serial No. 109,860.Divided and this application filed [1117 4928. Serial 110. 278,589.Renewedfebruary 28, 1931.

- The novel fin and condenser construction, oil and refrigerantseparating arrangement, refrigerator evaporator, and combination of thiseva orator with a refrigerator cabinet,

the provision of an improved machine of this character which shall besimple in con- 16 struction, quiet and eflicient in operation, durablemanufacturable at relatively low cost and have other desirable qualitieswhich ad'a t it for such use,

- The machine involving my invention employs a refrigerant which boilsat a relative low temperature and is caused to pass t rough a cyclewhich consists in allowing the refri rant in the liquid form toevalporate an thus absorb heat, compressing .t e

vaporized refrigerant, and removing the heat therefrom to cause it'tocondense into the liquid form again, this cycle being continu- "ouslrepeated during the operation of the mac e.

My invention will be better understood from the following descriptiontaken in connection with the accompan ing drawings, and its scope willbe p'ointe out in the appended claims. 4 I i Referring to the drawings,Fig. 1 is a vertical sectional view of a machine embodying my invention;Fig. 2 is a cross sectional view thereof taken on the line 22 of Fig. 1;Fig. 3 is an enlarged fragmentary view of Fig. 1; -4 Fig. 4 is a crosssectional view of parts shown in Fig. 3; Fig. 5 is a fragmentar crosssectional view taken on line 5-5 of ig. 4;

Fig. 6 is a cross sectional view taken on line f 6-6 of Fig. 2; andFig.7 is a perspective 5 oil pump.

In the drawings I have shown at 1, by way of. example only, the top orcover of'a refrigerator cabinet such as ma form a part 50 of a domesticinstallation. ounted on the view of the pistons of the compressor andtop 1 is the compressor and condenser unit 2 and beneath the top andwithin the cabinet is the evaporator .3. l

The compressor which in certain re cts is similar to that disclosed inthe ap cation of Clark Orr, Serial No. 756,336, ed Dec. 16, 1924, uponwhich Patent No. 1,725,472 was granted August 20, 1929, and assi ed tothe same assignee as the present app 'cation, comprises a frame 4 inwhich the drive shaft 5 is journalled and iii which the oscillatingcylinder 6 having the exhaust valve 7 is pivotally mounted by means ofthe trunnions 8. The moving parts are enclosed by the metal basing 9whose lower portion is enlarged and is connected with the upper portionby the flared portion 9. B means of lugs 10 secured to the'exterior othe enlarsed' portion and bolts 11, the casin is hel down tightlyagainst the bottom. p ate 12, which plate is supported on the top 1 bythe angle I covers this plate and the lower part. of the casing topresent a better appearance. Fit

ting 1n the up er ,portion of the casing 9 is the stator 16o an'electricmotor whose rotor 17 is secured to the shaft 5. The'upper ed e of theframe 4 is resiliently held against t e gtlator 16 by the pins 20 andthe 0011 springs Surrounding the casing 9 is the condenser comprisingthe coil of plpe 22 whose intake 23 is at the top of the casing. Aseries of fins 24, preferably of goodheat conducting material, extendradially from the casing 9 and have their outer edges provided withrecesses 25 for receiving the se arate turns of the condenser coil 22and ma 'ng good thermahconnection therewith. The inner ends of the finsare firmly secured to and in good heat conducting relatlon with theupper portion of the casing 9, as for example by soldering or brazing,and are shown, see Fig. 2, as formed in pairs each with. a shortconnecting portion in contact with the casing. Certain of the fins arefirmly secured also to the anchoring lugs 10, whereby they bridge theflared portion 9 and serve to stiffen the casing at this point. The fins24 intermediate their'inner and outer edges each have a row of holes 26rackets 13. A suitable apron 14' which,'as shown in Fig. 1, is closer tothe outer edge than the inner edge. By these fins, heat is conductedaway from both the casing 9 and the condenser coil 22, the row of holes26 forming a zero line of temperature gradient in the fins. The fins 24,therefore, serve the triple purpose of providing a support for thecondenser coil.,of, radiating heat from the casing, and of radiatingheat from the condenser coil.

As shown in Fig. 2, the frame 4 is formed with an arcuate wall 27forming a circular cavity centrally within which the cylinder ispivotally mounted. On the sides of the cylinder are the radialprojections or fins 28, which have sliding engagement with the wall 27.Thus there is formed an exhaust chamber between the end of the cylinderand the wall 27, and two pairs of similar expansion chambersof varyingsize between the fins 28 and the wall 27, the chambers comprising thefirst pair being larger than the exhaust chamber, and the chamberscomprising the second pair being larger than the first. At suitablepoints, the wall 27 is provided with small cut-away portions 27 whichunder the control of the fins 28, permit the compressed refrigerant topass successively from the exhaust chamber to the first and to thesecond expansion chambers, 'andthen pass intothe main casing. Thearrangement, preferably, is such that the oscillatory movement of thecylinder following a compression stroke admits compressed refrigerantfrom the exhaust chamber to the two first expansion chambers, and at thesame time refrigmuffles the sound thereof.

The vaporized refrigerant, which is preferably sulphur dioxide, after.being com- ..pressed, passes upward through thevmotor to the condenserintake 23. As the motor employed preferably has a very small air gap,

I have provided openings 29 through the.

rotor-17 for the free passageof the refrigerant. These openings, as willbe noted upon reference to Fig. 1, are inclined-so that the lower endis'at a greater distance from the shaft than the upper end. When therotor is in rapid rotation, any soil particles which are entrained inthe compressed refrigerant will be separated out by centrifugal force asthey pass through the openings and will be caused to-flow downward oraway from the intake 23.

The outlet end of the condenser coil 22 connects by the pipe 30 withcasing 31 forming a lever 34, operates the valve 35 to control the flowof liquefied refrigerant to the evaporator through pipe 36.

Machines of this type are designed to run intermittently in accordancewith the temperature in the cabinet. The starting and stopping of thedriving motor is automatically controlled and, when running, the motoris operated at relatively high speed. It is highly desirable, however,to have such a machine operate as quietly and as free from vibrationpossible. I have therefore devised improved means for balancing themoving parts of my machine such that at normal running speed noise andvibration are reduced to a very low value (see Fig. 3). As stated in thebeginning of the description, the compressor involves a singleoscillating cylinder 6 mounted on trunnions 8 which are journalled inthe frame 4. One end of the cylinder is closed by the valve 7 andprojecting from the other end thereof is the piston 41 which, for themost part, is made hollow to reduce its mass. The main drive shaft 5carries an eccentric member, shown in the present case as a crank pin42, which is journalled in a bearing sleeve 43 carried by the piston 41.Beyond the crank pin I provide the piston with the counterweight portion44 having such mass that the piston is substantially balanced on thecrank pin whereby the center of gravity of the piston and the center ofthe crank pin substantially coincide. In conjunction with the above,provide the shaft 5 with the counterweight 45 opposite the crank pin 42and having such mass that it substantially balances the combined mass ofthe crank pin and the piston. In this connection, it is to be understoodthat the part connecting the shaft and the crank pin is considered as apart of the crank pin. As so constructed, the moving parts comprisingthe shaft, crank pin and piston are so balanced that.,:even thoughoperated at a relativelyhigh speed, but little vibration and noise areperceptible.

To provide adequate lubrication of the various moving parts, thecylinder and piston are partially immersed in a bath 46 of lubricatingoil contained in the casing 9 from which the oil is forced to partsarranged above the bath. Referring to Figs; 4, 5 and 7 in one corner ofthe cylinder 6 and longitudinal thereofis the bore 47 in which slidesthe oil pump piston rod 48 whose outer end is fixed to the piston 41.The inner end of the bore 47 is-adapted to connect by the passage 49alternately with the passages 50 and 51- as the cylinder oscillates,whereby oil is pumped from the bath 46 to the lower trunnion bearing, toan oil groove in the cylinder wall and on up through passages 52 and 53to -the oil space 54 surroundingthat portion ms v of 'the drive shaftbetween its upper and lower bearings. Between passages 52 and 53 is thepiston 55 mounted to slide in a suitable bore in the frame 4, and whichis raised by oil pressure from the oil pump until the two passagesconnect with each other. Oil hole 56 in the shaft 5 leads from the oilchamber 54 down through the crank pin 42 to the bearing 43 therefor. Asecond oil hole 57 in the shaft leads from the oil chamber 54 to thespiral oil groove 57 by which oil is supplied to the thrust bearingabove, from which bearing oil may freely escape through suitablegrooves, and thus relieve the oil pump of excessive back pressure. Itwill be noted that force on the flow of oil. through the oil holes inthe rotating members must be given due consideration. Should the flowofoil through the oil hole 56 leading to'the crank pin, for example,become broken, the centrifugal force of oil at the entrance to this oilhole may be suflicient to prevent its entering the oil hole,

since oil hole 57 provides a relatively free path of escape for. theoil. Howeve'rs. by making the entrance portion of the oil hole 57 ofmuch larger diameter than the exit portion, and. larger than hole 56,the larger lgnass of oil contained in the larger portion of ole 57 will'prevent the flow of oil through this hole until the pressure in the oilspace 54 shall have built up sufliciently' to cause the oil to flowinward through this hole. Even after the oil flow is established throughthe holes 56 and 57 a certain predetermined pressure will be maintainedin the space 54 by reason of the larger size of the entrance portion ofoil hole 57, but this pressure willhot rise'to such avalue as to imposean excessive back pressure upon the oil pump.

When the machine is restarted after an interval of rest it may happen,especially if the main piston is on the suction stroke, that thepressure 'n the casing acting upon the forward en of the piston is sogreat that starting is made diflicult or even is prevent ed. To avoidthis condition, I have provided means by which'pressure is admitted tothe cylinder for equalizing the pressifres on the front and rear ends ofthe piston for the first few strokes, at least, or'until the motor hashad an opportunity to gain speed. 111 this connection, reference is madeto '3 and 4. The suction pipe 58 from the evaporator,

' after entering thev casing 9, connects with the casing 59) of-thecheck valve 60, beyond which itconnects by passage 61 with the port 62In the case of of the com ressor, thence by intake ort 63 to theinterior of the cylinder. Equa ization of, the pressure on oppositesides of the piston is effected by admitting pressure from the spacewithin the casing 9 to the rear end of the cylinder.. For this purpose,a small by-pass pipe 65 leads from the check valve casing 59 to theplate 66 covering tl1e=bore 41 where it connects with one side of thevalve seat 67 formed therein, the opposite side of the valve. seatconnecting by the passage 68 with theinterior of the casing 9. Piston 55has mounted therein a valve 70 lightly pressed outwardly by the spring71 7 so that when the piston moves upwardly under the pressure of oil,the valve 70 en valve 7 0 will-be held against its seat. When themachine stops, the loss of oil pressure permits the piston 55 todescend, thus open the compressor. If'the piston is on the suctionstroke, the'intake ports being thus in alignment, the pressures on thetwo ends of the piston are equalized. This condition will continue for:subsequent suction strokes until sufiicient oil has been pumped to raisethe piston 55 and close off the valve 70. Since the intake port,6 3 isspaced slightly from the end of the cylinder, I have provided thecylinder with a small opening 71 close to theend,

' which opening connects, when the piston is on the suction stroke, 72leading to the port 62.

' The evaporator 3, which, as stated above, is located within thecabinet of which I have shown only the upper portion and the cover 1, inthe present embodiment, is illustrated in the form of a horizontal fiatplate, preferably located near the cover but spaced therefromsufficiently-to permitits bein used as a. shelf upon yvhich may-be placearticles to be frozen, as for example,a tray 73 .for making ice cubes.The evaporator is shown comprising a rectangular casing having four sidewalls, atop, and a bottom, opposite side walls having lugs 75 throughwhich extend supporting bolts 76. The bolts pass through spacing sleeves77 and are secured into the' cover 1. Inlet pipe 36 from the float valveoil to pass between passages 52 and 53, the

ing the valve 70 by which the pressure in the casing 9 is communicatedwith'the intake of as i with a small opening casing 31 connects with theevaporator casing at one side thereof. The outlet or suction pipe 58 isalso shown connecting with the evaporator casing at one side thereof,butits connection differs from that of the inlet pipe in that theportion 80 thereof within the frigerant being about one half the depthof the casing. On the surface of the refrigerant there may be a thinlayer of oil, shown for example in Fig. 1 of the drawings by the heaviershade lines, the space above the liquid refrigerant and oil being ofcourse filled with vaporized refrigerant. The pipe 80 is shown having agoose-neck end portion 81, the open end 82 being close to the top wallof the casing, and in the curved portion are several small holes 83which are located slightly above the level of the liquid refrigerant.Through these small holes 83 any oil which collects on the surface ofthe liquid refrigerant is slowly withdrawn. This construction avoidsthe-necessity of exact leveling of the machine, for since the outlet islocated centrally of the evaporator casing,

' there may be considerable deviation from exact level without affectingthe relative level of the liquid at the outlet and without danger ofliquid refrigerant being pumped up by the compressor.

The cycle of operation of my machine, briefly, is a follows: The liquidrefrigerant in the evaporator 3 is vaporized as a result of heatreceived from the surrounding medium. The vapor drawn up through pipe 58by the compressor is compressed and discharged through the mufilerformed at the sides of the compressor cylinder 6 into the space withinthe casing 9. Passing up through the inclined discharge openings 29 inthe rotor of the driving motor, it enters the condensing coil 22 throughthe pipe 23. The compressed vapor, while in the casing 9, loses acertain amount of heat through the fins 24, and more heat is lost whileit traverses the coil 22 through direct radiation therefrom and throughthe same fins 24. The vapor finally condenses and flows through pipe 30into the float chamber 32, from .which it escapes through float valve 35into the evaporator 3.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:

1. A compressor comprising a drive shaft. an oscillatable cylinder, apiston therein, and means carried by the shaft and engaged by the pistonfor operating the same, said piston having a counterweight arrangedbeyond said means and said shaft having a counterweight arrangedopposite said means.

an eccentric member carried thereby, an os-,

2. A compressor comprising a drive shaft, a plston operatlng membercarried thereby, an osclllatable cylinder, and a piston therein engagingsaid operating member, said piston being substantially balanced on saidoperatlng member and said drive shaft having means thereon forsubstantially balancing the piston and the piston operating member.

3. A compressor comprising a drive shaft,

cillatable cylinder, and a piston therein having a bearing for theeccentric member, said piston having a counter-weight portion arpistonrod fitting said bore, forming an oil pump, said cylinder and framehaving other cooperating passages and parts for controlling the flow oflubricating oil.

5. A compressor comprising a frame, a

shaft journalled therein. oil ducts extending through the shaft from theperiphery thereof, one of said ducts providing a relatively free escapefor oil, oil pumping means in communication with both of said ducts,said one duct having the entrance portion thereof enlarged whereby theoil therein produces a predetermined back pressure on the pumping means.c

' 6. A compressor comprising a frame, a shaft carrying an eccentricmember, spaced bearings for the shaft in said frame whereby an oilchamber is formed around an intermediate portion of the shaft, an oilpump adapted to supply oil to saidoil chamber, an oil duct leading fromsaid chamber through the shaft to said eccentric member, a second oilduct leading from said chamber through the shaft to a shaft bearing andproviding a relatively unimpeded flow of oil therethrough,

the entrance portion of said second oil duct having a diameter greaterthan the remaining port-ion thereof and greater than said first oilduct, wherebya predetermined oil pressure is maintained in said oilchamber.

7. A closed compression system having a refrigerant compressor thereinincluding a pistonand cylinder, oil pumping means, driving means for thecompressor and oil pumping means, and means responsive to a pump forequalizingthe refrigerant pressure on the opposite sides of the piston.

9. A compressor comprising a cylinder and piston for compressingrefrigerant, an

oil pump, common operating means for said piston and pump, means forminga passage connectlng opposite sides of sa1d piston, a

valve controlling said passage, and means responsive to a redeterminedpressure of oil for holding said valve close l0. A compressor includinga cylinder having intake and discharge ports, a by-pass affordingcommunication between the ports of said cylinder, oil pumping means, andmeans controlled by the pressure of said oil pumping means for openingand closing the by-pass between the ports of said cylinder. 7 11. Acompressor including a cylinder having intake and discharge ports, aby-pass affording communication between the ports of said cylinder, oilpumping means, and means including a valve and piston controlled by thepressure of said oil pumping means for opening and closing the by-passbetween the ports of said cylinder.

12. A compressor comprising an oscillatable cylinder, a piston therein,said cylinder having an intake passage spaced from the endthereof, andmeans effective at the initial suction strokes of the pistonto admitpressure to said passage, whereby the pressure on opposite ends of thepiston is partially equalized, said cylinder having an additionalpassage therein connecting the intake passage with the cylinder bore ata point glose to one end of the cylinder. 1

13. A compressor comprising a frame, a cylinder oseillatably mountedthereon, a piston in the cylinder, said frame and cylinder havingcooperating ports for controlling the passage of refrigerant, saidcylinder having a'longitudinal bore in a wall thereof forming an oilpump cylinder, a piston therein, said frame and cylinder also havingcooperating ports for controlling the flowof oil from said oil pump.

14. A compressor comprising a frameand an oscillatable cylindermountedtherein, said frame and cylinder cooperating to form a pocket betweenthem, and means for directing the exhaust from said cylinder throughsaid pocket.v I i 15. A compressor comprising a. frame having an openingtherein, and an oscillatable cylinder mounted therein, said cylinderhaving projections thereon forming a pocket with said frame, and meansfor directing the exhaust from the cylinder through said pocket.

J 16. A compressor comprising a frame having an opening therein, andanoscillat- 55 able cylinder mounted therein, said cylinder havinglateral projections thereon forming with the frame a plurality ofcommunicating pockets, and means for dlreoting'the exhaust from thecylinder successively through said 60 pockets.

17. A compressor comprising a frame having a circular opening therein,and an oscillatable cylinder mounted therein, said cylinder havin aplurality of fins project- 66* from the si es thereof forming withtherein, said cylinder having a pluralityl of laterally projecting finsengaging the wa of said opening and thereby forming a plurality ofexpansion chambers of varying size, the a Wall of said opening beingformed with passageways cooperatingwith said fins as the cylinderoscillates, whereby the exhaust from the cylinder is successivelyadmitted to and discharged from the expansion chambers.

19. A compressor including a cylinder having intake and discharge ports,a casing enclosing thecompressor, said cylinder dis- .charging into saidcasing, a piston in said cylinder having the crank end thereof subjectto the pressure in said casing, oil pumpin means actuated in accordancewith the spec of the compressor, and means controlled by the pressure ofsaid oil pumping means for equalizing the pressure on opposite sides ofsaid piston.

' 20. .A compressor including a cylinder having intake and dischargeports, a casing enclosing the compressor, said cylinder discharging intosaid casing, a piston in said cylinder having the crank end thereofsubject to the pressure in said casing, oil pumpin means actuated inaccordance with the spec of the compressor, and means including a valveand oil actuated piston controlled by the pressure of said oil pumpingmeans for equalizing the pressure on opposite sides of said pistoin g21. A compressor including an oscillating cylinder having trunnion, arame-,,having a bearing supporting said trunnion and a bore in alignmentwith said bearing, oil pumpin means actuated inaccordance with the specof the compressor, and means including a piston arranged in the .bore ofsaid frame and controlled by the pressure of said oil pumping means forequalizing the pressure on opppsite sides of said piston.

22. A compressor including an oscillating cylinder having a trunnion, aframe having a bearing supporting said trunnion and a bore in alignmentwith said bearing, means including a piston arran ed in the bore of saidframe for loading an unloadingsaid compressor, and means controlled inaccordance k with the operation of said compressor for operating saidunloading means.

23. A refrigerating machine including a closed compressionsystem-containing oil, a

motor and a refrigerant compressor enclosedmeans responsive to oil,pres- 'n said system, hure for controllin loading of said compressor,and means inc uding a pump for the oil in said system and driven by saidmotor for controlling loading of said compressor.

24:. A refrigeratingtmachine includinga,

closed compression system containing lubricating oil, a motor and arefrigerant compressor enclosed in said system, means driven by saidmotor for supplying the oil in said system under pressure to lubricatesaid machine, and means controlled by the pressure of oil delivered bysaid oil supplying means for controlling loading of said compressor.

. 25. A refrigerating machine including a closed compression systemprovided with a casing containing a body of oil, a motor and arefrigerant compressor in said casing above the body of oil therein,means for supplying oil under pressure from the body of 01]. in

/ said casing, and means responsive to the pressure produced by said oilsupplying means for controlling loading of said compressor.

26. A refrigerating machine, including a closed compression systemprovided with a casing containing a body of lubricating oil, a

motor and a refrigerant compressor arranged.

in said casing above the body of oil therein, a lubricating system forsaid motor and compressor including means for supplying oil underpressure from the body of oil in said casing to said motor andcompressor vfor lubricating them, and means controlled by the pressureof oil in said lubricating system for loadin said compressor.

27. refrigerating machine including a closed compression system providedwith a casing containing a body of lubricating oil, a motor and arefrigerant compressor arranged in said casing above the body of oiltherein, means for supplying oil under pressure from the body of oil insaid casing to said motor and compressor for lubricating them, meanscontrolled by the pressure of oil from said oil supplying means forequalizing the pressure in the intake and exhaust passages of saidcompressor to unload said compressor until said motor attains normalspeed.

28. A refrigerating machine including a closed compression systemprovided with a casing containing a body of lubricating oil, a

motor and a refrigerant compressor arranged in said casing above thebody of oil therein, said compressor discharging into said casing, meansfor supplying oil under pressure from the body of oil in said casing tosaid motor and compressor for lubricating them, means a controlled bythe pressure of oil from said oil-supplying means for admitting highpressure gas from said casing to the intake of said compressor to unloadsaid compressor until said motor attains normal speed.

In witness whereof, I have hereunto set my hand this 16th day of May,1928.

CHRISTIAN STEENSTRUP.

